89 6g rack & pinion shake?

so here we go, the set up i have going on with my car is it has 18" rims on it stock suspnsion, just had an alignment. it still has a shake to the front end at around 50-65 mph, after the alignment. before the alignment the steering wheel was cocked to one side and shuck the whole time. last night i got a flat and had to put the donut on. while i was doing that i noticed that it seemed to have some play coming from between the tie-rod to the rack? the tie-rod seemed to be nice and tight how it should be? im woundering if the whole rack is worn internaly? or some thing loose in side the rack? oh and while t urning to one side or the other, you can turn more to one side then the other, and will cause the tire to rub the inner finder well. i wonder if the car hit a curb or some thing before i got it and maybe broke the stoper in the rack?